During summer the temperature can raise high degrees up to 50-60 degrees Celsius (° C.) while the relative humidity levels fluctuate in the range of 80% to 90%, especially in regions where are known to experiment high level of temperature and humidity such as Middle East. In these thermal stressful environments, mechanisms that the body usually uses to maintain the average normal body temperature are no longer enough to stabilize it which leads to a dehydration, a drop in blood pressure, and an increase in the heart rate. Outdoor workers work for long hours putting their health at risk without achieving their full potential due to the discomfort caused by the high temperature.
Cooling suit systems, such as portable cooling vests and pants have already been tested and studied previously. There are mainly three types of cooling methods used in this type of suit; gel cooling packs, evaporation by chemical reaction and gas expansion. The gel cooling packs are efficient with very effective long duration. However, they require long recharge time, continuous need for refrigeration, with little control or regulation. The evaporation by chemical reaction is controllable and reusable. However, it is complex, it has residual waste, it needs frequent replacement of chemicals, chemicals might not be inert, and the vessels might block from residual leftovers. The gas expansion method is simple, rechargeable, environmentally friendly and clean and shows high performance for efficiency. However it needs large amounts of working fluid and the fluid should be readily available.